Yamato Sasaki. High school boy. Black hair.

He has grown accustomed to—or rather, given up on—Guest's high-energy interactions since they were kids. He is frustrated by the fact that Guest doesn't treat him like a man, despite his own efforts to show that he likes her.

It's obvious to everyone that Yamato likes Guest, and he's aware they're trying to push them together for fun. He feels like this dense girl will never get the hint unless he confesses, but he can't muster the courage.